Stent That Dissolves After Blood Vessels Heal Enters Clinical Testing

Stents are tiny tubes inserted into diseased arteries to keep them open. The stent being tested, designed by REVA Medical Inc. of San Diego, is intended to act as a temporary scaffold to support the blood vessel during the healing process and maintain blood flow. It subsequently dissolves, leaving the patient free of any permanent implant.

Rutgers' Joachim Kohn is reporting on his new combinatorial biomaterials discovery process and the promise it holds for the medical device industry during TCT 2007 (Transcatheter Cardiovascular Therapeutics), the world's premier conference on interventional cardiology, which begins Saturday, Oct. 20 in Washington, D.C. Also reporting at the conference, Dr. Eberhard Grube of the HELIOS Heart Center in Germany describes the initial clinical experience from the RESORB trial that is evaluating the stent's safety in approximately 30 patients at multiple sites in Germany and Brazil.

Fully degradable coronary stents have been explored for more than 20 years. But, according to Kohn, no clinically useful products could be developed, in part, because of the lack of polymers that could meet the extremely demanding performance requirements. Kohn and his team addressed this problem by developing a library of degradable polymers comprising 10,000 theoretically possible compositions and applying combinatorial methods to identify the best possible biomaterial. The resulting material was selected for use in combination with REVA's novel stent design.

"We've applied novel design and advanced biomaterials solutions to create a significant advance in stent technology," said Dr. Robert Schultz, REVA's president. "This approach has allowed for us to bring it to the clinical stage quickly."

"Our unconventional discovery process integrates combinatorial polymer libraries, high-throughput testing and computational modeling. This results in a much faster path to prototype development and a reduction in the cost and risk associated with the use of new, proprietary biomaterials," said Kohn, a Board of Governors Professor who directs the New Jersey Center for Biomaterials at Rutgers.

Michael J. Pazzani, vice president for research and graduate and professional education at Rutgers, spoke of the impact of Kohn's work on the medical device industry. In addition to REVA, Rutgers has licensed the portfolio of Kohn's patents to several other companies. "One licensee was able to obtain FDA clearance for a new hernia repair device using one of Kohn's polymers on a three-year track from concept to FDA market clearance," Pazzani said. "Another is working with Kohn's combinatorial discovery process to identify an ideal polymer for their ophthalmic drug delivery device."

The significance of Kohn's work is related to its general applicability to many different biomaterials design challenges as evidenced by the diversity of products being commercialized using this discovery process.

The scientific foundations of the new biomaterials discovery process are being developed with support to the New Jersey Center for Biomaterials and the Kohn Laboratory from the National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health.

In collaboration with REVA, Kohn and his colleagues developed a polymer that is exceptionally strong and highly suitable for stent applications. In addition, the material was designed to be radio-opaque so it is X-ray visible, a property critical to the proper placement of the stent in the artery. It is also biodegradable and biocompatible.